Look, I remembered!
''Now for the new measurements. I've tried TL431 strapped
for its standard voltage, 2.5V, and for 5V. It turned out
quite noisy in both cases, but the noise figures turned out
very consistent.''
About TL431
Leds, Zeners
''Now for the new measurements. I've tried TL431 strapped
for its standard voltage, 2.5V, and for 5V. It turned out
quite noisy in both cases, but the noise figures turned out
very consistent.''
About TL431
Leds, Zeners
No, I can't spot anything else right now. But I must have seen one or two more comments about better than TL431 in the course of the years. Lets see what we can summarize from what we gathered up to now:
It seems that building with 12V or bigger Zeners and adjusting with Leds can be a short good Vref string of adequate noise for 12-40V shunts. 3.9V-4.7V Zeners and Leds look OK for below 12V. Avoid 5.6V-8.2V normal Zeners. Special tempco parts are nice if available.
All seem to fall in a logical picture. Haven't used low Zeners, haven't had problems.
It seems that building with 12V or bigger Zeners and adjusting with Leds can be a short good Vref string of adequate noise for 12-40V shunts. 3.9V-4.7V Zeners and Leds look OK for below 12V. Avoid 5.6V-8.2V normal Zeners. Special tempco parts are nice if available.
All seem to fall in a logical picture. Haven't used low Zeners, haven't had problems.
That reg shown is just my regulator but with TL431 Vref. Its obvious. And I just call it ''Simplistic Low Voltage Shunt''. It has been reported good enough by many who made it with a Zener. Both for practical noise with Riaa or other audio, and subjective sound. Now why with just some different values and another Vref can be called ''No Noise'' it just escapes me.
Attachments
Me I got it. But I have to clear things for people that may have not followed either the reg story or our individual styles. Remember that people will bump on threads in the years to come even.
As I wrote above, what is really needed is a nice PCB design. Vref options are easy to include too. I think if using a TL431, Vout variability is a great add on.
Anybody good in PCB?
Remember that people will bump on threads in the years to come even. As I wrote above, what is really needed is a nice PCB design. Vref options are easy to include too. I think if using a TL431, Vout variability is a great add on.
Anybody good in PCB?
As a bandgap device it owes to be noisier than LEDs or avalance Zeners people explained in that noise thread I linked. Its good thing is temperature stability. Also low impedance, being a shunt device. That helps PSRR. Plus its variable. My idea was to use a single Zener (above 12V I have only made or seen made, except JWB's 9V one that used a low quiet Zener (away from bad transition zone) plus 3 smt LEDs.). He had to, since he would be bang on worse Zener choice else. To help the low impedance and PSRR thing I used a low pinch off IDSS CCS to be able to work right under Vbe margin, for the rather high voltage/impedance Zeners. In practice it worked fine. And its capacitor bypassed.
Salas said:
Yes, they require one to ask for a quote. It doesn't look like the kind of place where you just buy a few parts.
Now, IMHO, the probable benefit is not great enough compared to the effort of getting these parts. I'll pass. Whoever has them handy should compare against a regular 1n47xx zeners or anything else that fancies them.
There will be a few challenges yet to overcome in building a regulator whose weakest link is just the voltage reference. We should be happy to get to that point. Are we there already?
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